1. Context

A powder is an assembly of heterogeneous solid particles dispersed in a continuous gaseous phase, between which a multitude of interactions (van der Waals, capillary, electrostatic, etc.) take place. The overall behavior of a powder depends directly on these interactions and on the physical characteristics of the solid particles [J 2 245] .

Particle size is undoubtedly the most sought-after parameter for a powder, both for predicting its behavior and for calculating the operations that involve it: storage, flow, separation, fluidization, heat exchange, chemical reactions, dispersion, dissolution, etc. And yet, what does particle size mean for a powder? And yet, what does size mean for a powder? For a spherical particle, knowing only its diameter (or radius) enables us to rigorously...